1. Field of the Invention
The present invention generally relates to a roll-like printing paper wound around a paper spool, a video printer using such roll-like printing paper and a method of detecting a remaining quantity of a roll-like printing paper. More particularly, this invention relates to a roll-like printing paper having a detection portion formed on a paper spool to detect a rotation of the paper spool wherein the rotation of the paper spool can be detected by the detection portion and a video printer and a method of detecting a remaining quantity of a printing paper in which a rotation of a paper spool of this roll-like printing paper is detected and an alarm is displayed if it is determined based on the detected paper spool rotation that the remaining quantity of the roll-like printing paper approaches to its end.
2. Description of the Related Art
Heretofore, there has been a video printer capable of printing a color image on a printing paper about the size of a postal card: This video printer may use an ink ribbon having a sublimation dye or a molten pigment coated thereon. FIG. 1 shows an example of an ink ribbon using a sublimation dye.
As shown in FIG. 1, this ink ribbon 55 may comprise a ribbon body 56 formed of a belt-like transparent film and thermal dye belts 57 of predetermined length coated (printed) along the longitudinal direction of the ribbon body at a constant interval repeatedly. As the dye belts, there may be generally used yellow (Y) dye belts 57Y, magenta (M) dye belts 57M and cyan (C) dye belts 57C which are complementary colors. A picture change sensor mark 60Y may be formed on a vacant area 58Y provided ahead of the Y dye belt 57Y, and color change sensor marks 60M, 60C may be respectively formed on vacant areas 58M, 58C respectively provided ahead of the M dye belt 57M and the C dye belt 57C.
FIG. 2 is a diagram showing a video printer having an ink ribbon and a printing paper loaded thereon. The ink ribbon 55 of predetermined length may be wound around a supply spool 62, and a tip end thereof may be wound around a take-up spool 63. A roll-like printing paper 71 may be rotatably attached to a printing paper roll presser, not shown, through a paper spool 70. A thermal head 68 serving as a print head and a sensor mark detection means 72 for detecting the sensor marks 60Y, 60M, 60C may be disposed between the pair of spools 62, 63. A platen roller (platen) 69 may be disposed on the opposite side of the thermal head 68 across the ink ribbon 55. The platen 69 may cause the ink ribbon 55 to be urged against the thermal head 68, and may transport the printing paper 71 inserted between the platen 69 and the ink ribbon 55 in cooperation with transport rollers 73, 74.
Such video printer 75 should perceive that the roll-like printing paper 71 approaches to its end after the printing paper was supplied from the platen 69 or the like and the rewinding of the printing paper was finished. To this end, there has hitherto been proposed a method of perceiving the portion near the end of the printing paper 71 by a plurality of detection marks 77 formed near the end of the printing paper 71 as shown in FIG. 3 or a plurality of perforations 78 perforated near the end of the printing paper 71 so as to be detected by an optical sensor as shown in FIG. 4. FIGS. 3 and 4 are diagrams showing the roll-like printing paper from the rear side.
According to the method of perceiving the end of the printing paper by marks provided near the end of the printing paper or by the perforations that can be perceived by the optical sensor, additional manufacturing process such as forming the detection marks 77 on the roll-like printing paper continuously manufactured or forming the perforations 78 that can be perceived by the optical sensor should be required. Unavoidably, there arises a problem that the number of production process increases to lower a production efficiency.
Also, since the whole of the printing paper cannot be used because the printing paper has the portion in which the marks 77 are formed or the perforations 78 are formed, a loss of printing paper may increase. Further, since the end of the printing paper is perceived by the marks or the perforations formed near the end of the printing paper, even though the end of the printing paper can be perceived, a remaining quantity of printing paper could not be perceived in advance.
It is an object of the present invention to provide a roll-like printing paper in which the approach of the printing paper to the end can be detected and displayed without effecting special processing on the printing paper additionally to thereby solve the above-mentioned problems, a video printer using such roll-like printing paper and a method of detecting a remaining quantity of a printing paper.
A roll-like printing paper according to this invention is a roll-like printing paper wound around a paper spool in which the paper spool has formed thereon a detection portion for detecting a rotation.
A video printer according to the present invention comprises a detection portion provided on a paper spool around which a printing paper is wound so as to detect a rotation of the paper spool, a rotation detection means for detecting the rotation of the paper spool by the detection portion and a control means for determining based on the paper spool rotation detected by the rotation detection means whether or not a remaining quantity of the roll-like printing paper wound around the paper spool approaches to the end and displaying a first alarm on a display means if the remaining quantity of the roll-like printing paper approaches to the end.
A printing paper remaining quantity detection method according to the present invention comprises the step of detecting a rotation of a paper spool around which a printing paper is wound, determining based on the detection rotation of the paper spool whether or not the remaining quantity of the roll-like printing paper wound around the paper spool approaches to the end and displaying an alarm on a display means if it is determined that the remaining quantity of the roll-like printing paper approaches to the end.
The roll-like printing paper according to the present invention may become possible to detect the rotation of the paper spool by the detection portion provided on the paper spool.
In the video printer according to the present invention, when the rotation detection means detects the rotation of the paper spool by the detection portion provided on the paper spool, it is determined by the control means based on the detected rotation of the paper spool whether or not the remaining quantity of the roll-like printing paper wound around the paper spool approaches to the end. If it is determined that the remaining quantity of the roll-like printing paper approaches to the end, then the display means displays a first alarm.
The printing paper remaining quantity detection method according to the present invention comprises the step of detecting the rotation of the paper spool around which the printing paper is wound, determining based on the detected rotation of the paper spool whether or not the remaining quantity of the roll-like printing paper wound around the paper spool approaches to the end and displaying the alarm by the display means if it is determined that the remaining quantity of the roll-like printing paper approaches to the end.